There is considerable interest in being able to reshape certain aspects of the mitral valve of certain patients in order to improve the functioning of that valve (e.g., to improve closure of the valve leaflets and thereby reduce or eliminate mitral regurgitation). Prior Hindrichs et al. U.S. patent application publications 2004-0186566 and 2007-0049942 show various techniques for doing this on the basis of relatively low invasiveness of the patient's body (e.g., percutaneously via catheter or catheter-like instrumentation). An illustrative approach shown in those prior patent applications is to drive a first screw-type anchor or a first pair of such anchors through the wall of the patient's coronary sinus and into adjacent heart muscle tissue that is in turn at or near a first point along the annulus of the mitral valve. A second screw-type anchor or a second pair of such anchors may be driven into the wall of the right atrium outside the ostium of the coronary sinus and at or adjacent to another point along the annulus of the mitral valve. A tether structure extends between the two anchor structures. The length of this tether structure can be shortened. This shortens the distance between the two anchor structures, which in turn shortens the length of the mitral valve annulus in this vicinity. Shortening the mitral valve annulus in this way can be beneficial to mitral valve performance (e.g., by improving the ability of the mitral valve leaflets to close and prevent undesirable blood regurgitation through the mitral valve).
Improvements to make apparatus of the type described above simpler and easier to use and capable of giving better results are always being sought.